Heat insulating batts and blankets are utilized in exhaust gas systems in order to provide heat insulation for acoustic and aftertreatment devices of the system to control the heat exchange to and from the devices. It is known, for example, to place heat insulating blankets between adjacent wall surfaces of such devices with the material of the heat insulation blanket being compressed to provide a desired installed density for the material to help maintain the heat insulating blanket in its mounted position via frictional forces between the blanket and the adjacent wall surfaces. Such a structure is shown in U.S. Ser. No. 12/696,347, filed Jan. 29, 2010 by Keith Olivier et al., entitled “Method of Producing an Insulated Exhaust Device”, the disclosure of which is hereby incorporated by reference. It is also known to provide heat insulation blankets around the exterior of such exhaust gas system devices.
The heat insulation properties of the blanket are dependent on, inter alia, the density of the blanket, and proper design of such devices requires that the density of the blanket be considered. It can, nonetheless, be difficult to ensure that the proper density/compression is provided and maintained for such blankets, particularly with external insulation blankets which are on the outer side of the devices.
The present invention is directed to overcoming one or more of the problems set forth above.